In texas, a reward for information leading to whoever gunned down a texas prosecutor. The man who made his name fighting organized crime was gunned down in cold blood. Here's abc's mark greenblatt. Reporter: Murder ad daylight this weekf one of texas' toughest prosecuting attorneys. Now has a small army of investigators working seven days a week. Police say mark hasse was gunned down by one, or perhaps two, shooters. Right next to the courthouse. His boss told abc news that he was fearless in putting the woers bad guys behind bars. He ran across the baddest guys in this part of the world. Reporter: Prosecutor of 30 years, in dallas, before moving to nearby kaufmann county where he never backed down. There's no reason to believe that there wouldn't be someone out there that might have an ax to grind. But certainly this carries it to an extreme. Reporter: Only deepening the mystery is, a local attorney tells abc that he claimed that he was recently threatened and left the courthouse daily with his gun drawn. But a district attorney says that's not true. If he was getting any kind of threat, he would let somebody know so we could do something about it. Reporter: He's making a pledge now to honor the man known for putting others away by not letting this one get away. Mark greenblatt, abc news, new york.

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